Arty computers

[Chuck Guzis]

On 3 Feb 2007 at 22:38, Jim Leonard wrote:

> Could you clarify which 808x CPUs in particular you're referencing in 
> the above?  There isn't a single case from 808x to 486 where that code 
> will beat rep movsb.  Were you referring to Pentiums and higher?

Just so--when x86 went superscalar, there was a significant 
difference in the execution rate of V-pipe instructions as compared 
to the more complicated CISC-type ones such as MOVSB.  Which is also 
why the DEC/JNZ turns out ot faster than the LOOP.

I seem to recall a DDJ article around the time of the introduction of 
the Pentium that warned about this.

Cheers,
Chuck